title: Sesquiterpenoids from myrrh inhibit androgen receptor expression and function in human prostate cancer cells.
abstract: OBJECTIVE
  To examine whether two naturally occurring sesquiterpenoids (ST1 and ST2) with anti-proliferative activity in prostate cancer cells inhibit androgen receptor (AR) signaling.
  
  
  METHODS
  Human prostate cancer cell lines LNCaP and PC3 were used. The expression of AR, AR translocation into the nucleus, and expression levels of AR coactivators ARA70 and steroid receptor coactivator-1 (SRC-1) in LNCaP cells were examined using real-time PCR and Western blot. Changes in prostate-specific antigen (PSA) protein levels, PSA promoter activity, and androgen response element (ARE)-mediated reporter gene activity were examined using enzyme-linked immunoabsorbent assay (ELISA) and transient transfection assays. Co-immunoprecipitation was performed to analyze the interaction between AR and the AR coactivators in ST1- and ST2-treated cells.
  
  
  RESULTS
  In LNCaP cells, ST1 and ST2 (40 μmol/L) led to a significant decrease in the expression of AR as well as a reduction of AR translocation into the nucleus, but had no effect on AR protein translation. ST1 and ST2 treatment also resulted in a significant decrease in the level of PSA protein secreted into the medium and was able to suppress PSA promoter-dependent and ARE-dependent luciferase activity. Furthermore, decreased expression of ARA70 and SRC-1 was observed when LNCaP cells were exposed to ST1 and ST2, which interfered with their ability to interact with AR.
  
  
  CONCLUSIONS
  The observations suggest that suppression of AR transactivation by ST1 and ST2 may be mediated, in part, by inhibiting AR nuclear translocation and/or interfering with the interaction between AR and its coactivators ARA70 and SRC-1. Therefore, sesquiterpenoids could be developed as novel therapeutic agents for treating prostate cancer.
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Ji-nan, China.
authors.forename: Xiao-ling
authors.initials: XL
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Kong
authors.forename: Tao
authors.initials: T
authors.lastname: Shen
authors.forename: Charles Y F
authors.initials: CY
authors.lastname: Young
authors.forename: Hong-xiang
authors.initials: HX
authors.lastname: Lou
authors.forename: Hui-qing
authors.initials: HQ
authors.lastname: Yuan
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D029744:Commiphora; D006801:Humans; D008297:Male; D058990:Molecular Targeted Therapy; D008517:Phytotherapy; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D011944:Receptors, Androgen / Q000378:metabolism*; D012717:Sesquiterpenes / Q000494:pharmacology*; D013729:Terpenes / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D011944:Receptors, Androgen; D012717:Sesquiterpenes; D013729:Terpenes; C014119:myrrh oil